JP2002200182A - Method for confirming radiation irradiation position - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method for confirming a radiation irradiation position that helps correctly confirm the positional relationship between an irradiation position and an affected site during radiation irradiation. SOLUTION: An X-ray source 14 is provided on the extended line of an irradiation axis of radiation, the irradiation position is irradiated with an X-ray from the X-ray source 14 when radiation is not being irradiated, the image is taken and the position of an affected site is confirmed in real time during radiation irradiation, whereby as the positional relationship between an irradiation position and an affected site can be correctly confirmed even during the irradiation of radiation, radiotherapy that has previously required an advanced operation technique and experience can be executed easily and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation irradiation position confirming method for irradiating an affected part of a patient with radiation such as a proton beam or heavy radiation for treatment.

[0002]

2. Description of the Related Art In recent years, a radiation therapy method which has attracted attention as one of methods for treating malignant tumors such as cancer is a method in which an ionizing radiation such as a proton beam or a heavy ion beam from a radiation source is irradiated by a bending magnet or the like. It is guided to the vicinity of the affected area, adjusted with a radioactive adjustment member such as a collimator or bolus, and then locally irradiated to the affected area to kill only cancer cells. Compared to treatment methods such as surgery and medication, it has excellent advantages such as significantly reducing the physical and mental burden on the patient.

[0003]

By the way, in such a radiotherapy method, it is necessary to fix a patient to a bed before irradiation treatment and to accurately position the patient so that only the affected area is irradiated with radiation. Although it is important, the irradiation condition cannot be confirmed accurately after the start of irradiation in the past, and therefore, there is a problem that radiotherapy requires advanced operation techniques and abundant experience.

That is, in the conventional radiotherapy method, after the patient is fixed to the irradiation bed of the treatment apparatus, the affected part and the irradiation position are accurately positioned from the irradiation axis direction and the orthogonal direction using an X-ray imaging apparatus. After the positioning, the X-ray imaging apparatus hinders the irradiation of radiation, so it is necessary to withdraw from the irradiation position. Therefore, after the start of irradiation, the position of the affected part cannot be confirmed from the irradiation axis direction, and if the irradiation position shifts due to movement of the patient during irradiation, it is possible to accurately grasp the degree of the shift. could not.

Accordingly, the present invention has been devised to effectively solve such a problem, and an object of the present invention is to accurately confirm the positional relationship between an irradiation position and an affected part even during irradiation. It is intended to provide a new method for confirming the irradiation position of radiation.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a radiation emitted from a radiation source is bent by a deflection electromagnet and then applied only to a predetermined affected part intermittently. In a radiation irradiation treatment method adapted to
An X-ray source is provided on the irradiation axis of this radiation, and when the radiation is not irradiated, the X-ray source irradiates the irradiation position with X-rays. It is to confirm with.

[0007] This makes it possible to accurately grasp the positional relationship between the irradiation position and the affected part even during irradiation, and if a shift is confirmed, the irradiation of radiation is stopped or the shift is corrected. Appropriate processing can be immediately performed.

Further, when the X-ray is irradiated from the X-ray source to the irradiation position, a passing hole is formed outside the bending position of the bending electromagnet. By irradiating the irradiation position with the X-rays from the X-ray source, it is possible to accurately irradiate the irradiation position with the irradiated X-rays without directly interfering with the bending electromagnet or its casing.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a radiotherapy apparatus used in the radiation irradiation position confirmation method of the present invention.

In FIG. 1, reference numeral 1 denotes a deflection electromagnet for guiding radiation such as proton beams and heavy ion beams generated from a radiation source to the vicinity of an affected part of a patient, and reference numerals 2 and 3 denote radiation doses emitted from the ends of the deflection electromagnet 1. 4 is a range shifter that adjusts the position in the irradiation depth direction of radiation, and 5 is 10 to 20 cm from the patient's skin to determine the irradiation range of radiation.
, A bolus 6 near the multi-leaf collimator 5 for adjusting the range of radiation into the living body, and 7, 8 the axes of the radiation guided by the bending electromagnet. X and Y scanning electromagnets for adjusting, 9 are scatterers for adjusting the irradiation beam width of radiation,
Reference numeral 0 denotes a fixed bed that is movable while fixing the patient, 11 denotes a turning mechanism that turns these irradiation mechanisms around the patient,
These configurations and operations are the same as those of the conventional radiation irradiation apparatus.

In the vicinity of the multi-leaf collimator 5, a positioning X-ray source (X-ray tube) 12 is provided so as to be movable in the direction of an irradiation position (irradiation axis). The X-rays are radiated, and the transmitted X-rays are received by an X-ray imaging tube 13 provided at the bottom of the affected part to obtain a transmitted image.

In the present invention, another X-ray source (X-ray tube) 14 for position confirmation is provided on the irradiation axis.
Is provided.

The position confirming X-ray source 14 is provided outside the emission end of the bending electromagnet 1 gently curved from the upper side to the lower side and on an extension of the radiation irradiation axis.
X-rays are irradiated to the irradiation position from an extension of the irradiation axis, and the transmitted X-rays are received by an X-ray imaging tube 13 provided at the bottom of the affected area similarly to the X-ray source for positioning 12 so as to obtain a transmission image. Has become.

That is, as shown in FIG. 2A, a through hole 15 is formed on the outer peripheral side of the emission end of the bending electromagnet 1 and is located on an extension of the irradiation axis. By irradiating the deflection electromagnet 1 with X-rays from the X-ray source 14, X-rays can be irradiated to the same position as the radiation irradiation position without interfering with the deflection electromagnet 1.
As shown in FIG. 1, the bending electromagnet 1 is formed by arranging so-called H-shaped magnets having an H-shaped cross section along a radiation path, so that the radiation is guided along the center. Has become.

Next, an example of the radiation irradiation position confirmation method of the present invention using the radiotherapy apparatus having the above-described configuration will be described.

First, the patient is fixed on the fixed bed 11, and the fixed bed 11 is moved so that the affected part is located at the irradiation position. Then, the X-ray source 12 for positioning is moved to the irradiation position of the radiation. Irradiates the affected area with X-rays, and monitors the X-ray transmission image on a CRT or the like, while the fixed bed 1
1 or the turning mechanism 10 side is finely adjusted to accurately position the irradiation affected part and the irradiation position. Note that, depending on the type of the affected part (organ), it may be difficult to see in the X-ray image. Therefore, before positioning, a metal piece or a metal sphere is buried directly before or in the vicinity of the irradiated part, and this is used as a guide. (Marker) in some cases.

Next, when the irradiated diseased part and the irradiation position are accurately positioned in this way, the positioning X-ray source 12 is shifted from the irradiation line so as not to interfere with the radiation, and then a predetermined amount is moved from the radiation source. The radiation is generated and guided to the affected part by the bending electromagnet 1, and the irradiated part is irradiated linearly from the emission end. Usually, the radiation is continuously applied from the start to the end of the treatment. Instead, the pulsed operation, that is, the irradiation is performed intermittently over several minutes at regular intervals. For example,
If one irradiation time is 0.5 seconds, then 1.5 times
An irradiation method is employed in which an irradiation pattern of a 2-second cycle is repeated over several minutes so that no irradiation occurs for a second.

Therefore, during this radiotherapy,
Since the non-radiation time occurs at regular intervals, the monitoring X-ray source 14 outside the bending electromagnet 1 irradiates the irradiation position with X-rays using the non-radiation time.
Then, only the X-ray reaches the affected part along the radiation irradiation line, passes through it, is obtained as a transmission image by the X-ray imaging unit 13, and the positional relationship between the affected part and the irradiation position in that time zone is real-time. Can be observed. The dose monitors 2 and 3 located between the exit end of the bending electromagnet 1 and the affected part count the dose irrespective of radiation and X-rays. It is desirable to provide a circuit or the like for preventing the counting or counting during the classification or X-ray irradiation.

If, as a result of the observation of the irradiation position by the X-rays, a deviation occurs between the radiation irradiation position and the affected part, the deviation can be quickly and accurately confirmed. For example, if the deviation is within the allowable value range, the radiation irradiation is continued as it is, and if the deviation exceeds the allowable value and may adversely affect a healthy organ, the position is corrected, Alternatively, it is possible to quickly and accurately take appropriate measures such as immediately stopping irradiation. It is ideal if X-rays can always be observed during treatment regardless of the presence or absence of radiation irradiation. However, irradiation with X-rays at the same time as irradiation is currently not permitted due to legal regulations. .

As described above, in the method of the present invention, a new X-ray source 14 is provided on the irradiation axis of radiation, and X-rays are irradiated from the X-ray source 14 to the irradiation position when radiation is not being irradiated. Therefore, since the irradiation position and the position of the affected part, which could not be accurately confirmed by the positioning X-ray source 12 or the like, can be confirmed in real time during radiation irradiation, advanced operation techniques as in the conventional method are used. It is possible to always provide the optimal radiation treatment easily without requiring any experience.

Here, in the present embodiment, the X-ray source 14 is provided on the upstream side in the irradiation direction of radiation,
The X-ray source 14 is provided at the bottom of the affected part of the patient as shown in FIG. 3, and a new X-ray imaging is performed on the upstream side in the irradiation direction of the radiation. The position may be confirmed by installing the unit 16 and irradiating X-rays from the bottom of the affected part of the patient.

As shown in FIG. 2B, when the bending electromagnet 1 for guiding radiation is a so-called C-shaped magnet, when the notch 17 is located on the outside. , It becomes possible to irradiate the irradiation position as it is from the notch 17,
As described above, there is no need to newly process the passage hole 15 for passing X-rays as in the case of using the bending electromagnet 1 composed of the H-shaped magnet.

Further, since the position confirming X-ray source 14 can be used also as the positioning X-ray source before the start of the irradiation treatment, the multi-leaf collimator 5 conventionally installed is used.
It is also possible to omit the positioning X-ray source 12 near.

As a specific example of the irradiation conditions from the position confirmation X-ray source 14, a lung (water equivalent) is provided under the condition that the distance between the X-ray source 14 and the X-ray imaging unit 13 is 1.3 m. 20cm), an X-ray tube setting of 85 kV,
The position of the affected part can be sufficiently confirmed by fluoroscopy at about 23 mA and about 30 ms. Also, their distance is 3.5m
X-ray tube setting 85kV, 170mA, 30ms
This is possible with a value sufficiently lower than the upper limit value (85 kV, 600 mA, 30 ms) of a general-purpose medical X-ray tube. Therefore, even when a binary degrader or the like is installed above the collimator 5 as well as the dose monitors 2 and 3 and the range shifter 4 and the bolus 6 which are insertion devices, it is possible to sufficiently see through the affected part with general-purpose X-rays. I can say.

[0026]

In summary, according to the present invention, the positional relationship between the irradiation position and the affected part can be accurately confirmed in real time even during irradiation, so that conventional radiotherapy requiring advanced operation techniques and experience can be performed. It can be implemented easily and accurately. As a result, the reliability and effect of the radiotherapy are greatly improved, and excellent effects such as greatly contributing to the spread and promotion of the radiotherapy method are exhibited.

[Brief description of the drawings]

FIG. 1 is an overall schematic view showing one embodiment of a radiotherapy apparatus to which the method of the present invention is applied.

FIG. 2 is a transparent perspective view showing one embodiment of a bending electromagnet used in the method of the present invention.

FIG. 3 is an overall schematic diagram showing another embodiment of the radiation therapy apparatus to which the method of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bending magnet 2,3 Dose monitor 4 Range shifter 5 Collimator 6 Bolus 11 Fixed bed 12 X-ray source for positioning 13 X-ray imaging unit 14 X-ray source for position confirmation 15 Through hole

Claims (2)

[Claims] 1. A radiation irradiation treatment method in which radiation emitted from a radiation source is bent by a bending electromagnet and then applied only intermittently to a predetermined affected part, and an X-ray source is provided on an extension of an irradiation axis of the radiation. X-rays are irradiated from the X-ray source to the irradiation position when radiation is not being irradiated, and the image is taken to check the position of the affected part in real time during irradiation. Radiation irradiation position confirmation method. 2. The apparatus according to claim 1, wherein a passing hole is formed outside the bending position of the bending electromagnet, and X-rays are emitted from the X-ray source to the irradiation position through the passing hole. The method for confirming a radiation irradiation position according to claim 1.